Alarm raised by Paulo Artaxo, one of the world’s most influential researchers in the area of the environment and climate change, who lectured at the RCGI before going to COP27.
Even if we are able to substitute fossil fuels with those from renewable sources, it will be practically impossible to achieve net-zero carbon dioxide (CO2) emissions by 2050 without protecting the natural CO2 storage system of tropical forests, mainly in the Amazon, because they hold the largest stock of CO2 on the planet. The alarm was sounded by scientist Paulo Artaxo, Professor of the Physics Institute of the University of São Paulo (IF-USP) and lead-author of a chapter of the most recent report of the Intergovernmental Panel on Climate Change (IPCC) on Thursday, October 27, during a lecture at the annual conference of the Research Centre for Innovation in Greenhouse Gases (RCGI).
Artaxo is one of the world’s most influential researchers in the environment and climate change area, and was on his way to Sharm el Sheikh, Egypt, to participate in the 27th Conference of the United Nations on Climate Change, COP 27.
According to him, several studies, by different laboratories having distinct scientific strategies, indicate that current levels of climate change have already reached the point of no return, and that deforestation and degeneration of forests are some of the main driving factors. “In 10, 15 years, the changes that have established themselves will determine what the climate will be like over the coming centuries,” he said. And the conclusions of the most recent scientific studies, which he presented, are not good.
According to Artaxo, the climate issue is complex and its factors are heavily connected with each other. “Two months ago, a study was published showing that what is done here in the Amazon has a critical effect on precipitation in Himalaya, which provides water for some 1.6 billion people. Therefore, this shows that the atmosphere is a single entity and that everything is connected.” he stated.
In the Amazon, the inflexion point is the capacity of the forest to sustain itself. The transition process, led by deforestation, climate change, has already altered a number of the aspects of its eco system. One of them is photosynthesis, which is the process used by plants to produce energy, where capturing CO2 is essential. “Under the stress caused by higher temperatures, the quantity of carbon dioxide assimilated by photosynthesis in the forest is drastically diminishing,” he said.
What is being noted in several studies, says Artaxo, is that the flow of liquid carbon dioxide in the Amazon is diminishing. “When I began studying the region 30, 35 years ago, the Amazon was absorbing 1.5 tons of CO2. Now, that flow is practically zero. Zero, mainly because of the death of trees is increasing. And why is it increasing? Because of the growth of climate extremes, the increase in temperatures and lower precipitation levels.”
He gives the example of Siberia, where the capture and removal of CO2 from the atmosphere is extremely dynamic, with difference in the winter and in the summer. In the Amazon and the tropical forest of Africa, the CO2 reservoir is permanent. That is, once it is dispersed, the CO2 will remain permanently in the atmosphere.
The temperature of the planet tends to increase between 3.3 and 4 degrees Celsius, and the IPPC estimates an average of 4 degrees Celsius. “But the average temperature difference doesn’t mean much, because no one lives within an average temperature range. In Brazil, an average temperature difference like this one means that we will have temperature increases of 6.6 degrees Celsius. In the Arctic, Siberia, and the Canadian tundra, the increase could be as much as 7 degrees Celsius. That is an immense increase,” he emphasized.
Desertification process – Another important change is precipitation, or levels of rainfall. “Many areas of our planet are already becoming more arid, and one of them is the central region of Brazil and the eastern Amazon, where there has been a highly significant decrease in precipitation levels. Europe’s Mediterranean region (southern Spain, Portugal, and Italy) is in an accelerated desertification process, as are Central America and the central area of the U.S. “This brings up a critical ingredient for food production. And this is not a preview of the future. It is already happening.”
He points out that the food production system is responsible for 32% of the global CO2 emissions, and over the coming decades the emissions of this sector are estimated to increase by 50%. “How will the planet be able to produce food for 10 billion people and at the same time achieve net-zero? By not eating? So, basically, this situation goes way beyond the question of energy systems; we are talking about the need for a sustainable society.”
“Savannization” of the Amazon – According to Artaxo, deforestation of the Amazon is occurring at a rate of about 13,500 square kilometers per year (data for 2021). And that figure tends to be 27% higher in 2022. This change in the eco system is critical. “One inflexion point would be a change from a forest eco system to a type of savannah, with 10% of the original CO2 stored,” he said. Since a number of factors influence this trajectory, the question that remains is: “Will this transition between eco systems be smooth or abrupt, and will it be reversible? These are critical questions and we do not yet have a clear answer.”
Artaxo believes that science already has some sense of the issue of reversibility. Areas of the Amazon that were deforested 40, 50 years ago, and abandoned, have been going through a regeneration process, but with only 55% to 60% of the original biomass and one-third of the previous biodiversity.
Research by the Amazon Environmental Research Institute (IPAM) correlates the precipitation level, from arid to humid, with the biomass of the Amazon, the African rainforest, and that of southeast Asia. “The three rain forests are surprisingly quite different from each other, but they have a pattern. Where there is more rain, there is more biomass.”
Another aspect is that, between the three rain forests, the Amazon is the one that releases the most CO2 due to vegetation loss. “We are talking about something like 5.1% of the carbon dioxide out of a total of 120 billion tons of stored CO2.”
He reminds that the loss of carbon dioxide is not related merely to the deforested areas, because the adjacent areas are responsible for 36% of the Amazon’s CO2 emissions.
Extreme risk – According to Artaxo, most of the area of the Amazon is becoming more inflammable. This can be calculated by the deficit of vapor pressure, which is the quantity of water that plants release into the atmosphere. “We are also seeing significant changes in the hydrological cycle of the Amazon, with a growth in the volume of water in the rivers of the Amazon over the past 120 years. If the volume is growing, this means that less water is being reprocessed by the eco system.”
Another change is in the rainfall system, which, briefly put, is when the evaporated water from the Atlantic Ocean goes into the Amazon and from there to the rest of the country, providing rain needed by crops. “A study shows that we would be nearing the inflexion point if the precipitation is greater than one thousand milliliters and if the temperature variation is greater than 2.5 degrees Celsius,” he said. “Another study, by Carlos Nobre, presents an estimate that if there is a temperature increase of 4 degrees Celsius, or if 40% of the forest areas are deforested, all of the remaining forest areas will be lost. And we are halfway into this forecast.”
Artaxo believes that Brazil has a tremendous opportunity, by protecting the natural storage of CO2, of reducing carbon dioxide emissions by 44% over the next five years. It is important to remember that, although the U.S. and China are historically huge CO2 emitters, Brazil is not far behind. In 2021, it was the world’s seventh largest in terms of emissions, fourth in terms of emissions per capita, and sixth in historic emissions. Despite all that, in a review of the agreements on goals for reducing emissions last year, Brazil was the only country that increased its allowable emissions.
“We have a large biofuels program, which no other country has; a huge potential for absorbing CO2, but at the same time a number of vulnerabilities, with the agricultural sector being very sensitive to the climate, hydroelectric power generators that depend on rain, and 8,500 kilometers of coastline that is vulnerable to rising sea levels.
On order to analyze the present and the future, it is essential to look at the past, says Artaxo. A serious look at history shows that down through 500 million years the Earth’s climate oscillated constantly between warmer and cooler, with glacial and interglacial periods. “Over the past 10 million years, the Earth has remained in the warm interglacial period, which is where we are now, and that allowed human civilization to prosper. All of the life on Earth appeared over the last four million years. And every time there were extinctions of species, associated with the climate, and it happened several times, it took millions of years for the eco system to recover. So, any damage is very hard to recover, and this should be a lesson for us,” he emphasized.
According to him, analyses of the last 800,000 years show that the oscillation between glacial and interglacial periods are connected with the greenhouse gases and the global temperature. The problem is that this cycle of oscillations is now breaking down. “over the last 60, 70 years, the Earth left the cycle that had been recurring of 800,000 years. So we are taking the Earth out of this dynamic climate system, and we do not know where we are going,” he said.
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About the RCGI – O Centro de Pesquisa para Inovação em Gases de Efeito Estufa (RCGI) é um Centro de Pesquisa em Engenharia, criado em 2015, com financiamento da FAPESP e da Shell. As pesquisas do RCGI são focadas em inovações que possibilitem ao Brasil atingir os compromissos assumidos no Acordo de Paris, no âmbito das NDCs – Nationally Determined Contributions. Os projetos de pesquisa – 19, no total – estão ancorados em cinco programas: NBS (Nature Based Solutions); CCU (Carbon Capture and Utilization); BECCS (Bioenergy with Carbon Capture and Storage); GHG (Greenhouse Gases) e Advocacy. Atualmente, o centro conta com cerca de 400 pesquisadores. Learn more here.
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